# Identifiers, data carriers and GS1 Digital Link explained

> The identifier, the carrier and the resolver are three different things. Here's how they fit together.

## Key takeaways

- A QR code is the carrier, not the passport.

- A GTIN identifies a product class; item-level passports need serialisation.

- Control your resolver so destinations can change without reprinting codes.

## Three separate pieces

| Piece | What it is | Example |

| --- | --- | --- |

| Identifier | Names the object | GTIN + serial number |

| Data carrier | Physical access mechanism | QR code, NFC tag, RFID, Data Matrix |

| Resolver | Directs a scan to the right content | GS1 Digital Link resolver |

## GS1 Digital Link

GS1 Digital Link expresses identifiers such as GTINs, batch and serial numbers as web URIs. One code can serve point-of-sale scanning, consumers, repairers and regulators, and the linked content can change without replacing the printed code.

## Granularity

| Level | Identifier | Typical use |

| --- | --- | --- |

| Model | GTIN | Toys, detergents, many ESPR goods |

| Batch | GTIN + lot | Steel, chemicals, food-adjacent goods |

| Item | GTIN + serial | Batteries, luxury, high-value electronics |

## Choosing a carrier

- QR — cheapest, universal smartphone support, printed on label or product

- NFC — invisible, premium feel, tap-to-read, good for authentication

- RFID — logistics and inventory; not consumer-readable by phone

- Durability matters: the carrier must survive the product's expected lifetime, washing, heat or abrasion

## Keep links stable

Passports must stay reachable for the product's lifetime — ten years for detergents. Use a domain and resolver you control, and contract for data export so you can switch providers without breaking printed codes.

## Sources

- [GS1 Digital Link](https://www.gs1.org/standards/gs1-digital-link)

- [GS1 and the DPP](https://www.gs1.org/standards/standards-emerging-regulations/DPP)